’Rendement par bac’

Development of a procedure for the analysis of the composition of paper through research of known paper recipes and samples using the microscope and spot- and microchemical tests.
Bas van Velzen, specialisation Book and Paper

KNP-01-01This research focuses on the composition of paper since it was felt that, in looking at the objects they treat, paper conservators tend to base their treatment decisions mainly on what is on the paper, with little regard for what the paper itself is made of.

‚Rendement par Bac’ is an expression derived from recipes for paper furnishes produced by the Koninklijke Papierfabriek Nederland in Maastricht (NL) referring to the capacity of the Hollander beaters used. These recipes, dated between 1897 and 1972, describe the way certain papers were made and are given on the same papers they describe. This raises the opportunity to use these papers to check if microchemical tests and stains will reveal the correct composition of the paper. Also, a book of 1886 about papermaking gives on each first page of a quire the recipe for the paper used in that quire. This allows for the study of the state of the art of 19th and early 20th century papermaking which used a host of different materials.

Paper conservators know a lot about how paper is made and how it appears when degraded. Most paper conservators, however, do not check what they assume to be the furnish of the paper at hand. This neglect to gather information about the paper to be treated may have several causes:

  • what is on the paper is the reason the paper has to be conserved, not the fact that it is paper as such, so that the technique of what is on the paper is leading
  • the knowledge needed to describe paper accurately is spread over many fields of expertise (paper history, chemistry, paper chemistry, engineering, microscopy, botany etc.)
  • the tests to be used often contain nasty chemicals
  • often the tests do not keep well so that new ones have to be made at regular intervals, which demands considerable expertise given that the composition of the tests is critical
  • the best method (and best practice therein) of taking samples that are both small yet sufficient to be able to determine the composition of the paper is not yet well developed.

katoen-(zaadbol)-astrablauw---safranine-50x-klTherefore the aim of this research is to develop a method that will give the paper conservator the tools to easily and quickly gather the necessary knowledge about the paper to be treated. Different tests (currently 78 in number) to establish the paper furnish are evaluated and those that prove best to answer the conservators’ questions shall be put to the test. Finally, the relation between paper composition, the way the fibres were prepared and the resultant ageing behaviour of these fibres will be studied. In this way the paper conservator will be able choose the best treatment that respects both the technique on the paper as well as the paper itself.

Professor Dr Jørgen Wadum (UvA C&R); Dr Henk Porck (Royal Library, the Hague)

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